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| author | Amery Hung <ameryhung@gmail.com> | 2026-06-05 13:20:56 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-06-05 14:18:20 -0700 |
| commit | d83d4f63cb8f92aa6254dfc001eac0e41f5b2c35 (patch) | |
| tree | d239e1b512469d86914ff0913f6e1361d153d052 | |
| parent | ac7f6c9da6b6b46bba34a45c51603c81e7d42eb2 (diff) | |
| download | linux-d83d4f63cb8f92aa6254dfc001eac0e41f5b2c35.tar.gz linux-d83d4f63cb8f92aa6254dfc001eac0e41f5b2c35.zip | |
selftests/bpf: Use bpf_dynptr_slice() to read file dynptr in leak test
use_file_dynptr_slice_after_put_file() reads the dynptr via
bpf_dynptr_data(), which always returns NULL for a read-only file
dynptr, making the example confusing. Switch to bpf_dynptr_slice(), the
correct read API for file dynptrs, and read (rather than write) the slice
since it is read-only. The test still fails as expected.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Link: https://lore.kernel.org/r/20260605202056.1780352-6-ameryhung@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
| -rw-r--r-- | tools/testing/selftests/bpf/progs/file_reader_fail.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/tools/testing/selftests/bpf/progs/file_reader_fail.c b/tools/testing/selftests/bpf/progs/file_reader_fail.c index d5fae5e4cf9a..3bb9e2612f8f 100644 --- a/tools/testing/selftests/bpf/progs/file_reader_fail.c +++ b/tools/testing/selftests/bpf/progs/file_reader_fail.c @@ -87,7 +87,8 @@ int use_file_dynptr_slice_after_put_file(void *ctx) struct task_struct *task = bpf_get_current_task_btf(); struct file *file = bpf_get_task_exe_file(task); struct bpf_dynptr dynptr; - char *data; + char buf[1]; + const char *data; if (!file) return 0; @@ -95,15 +96,14 @@ int use_file_dynptr_slice_after_put_file(void *ctx) if (bpf_dynptr_from_file(file, 0, &dynptr)) goto out; - data = bpf_dynptr_data(&dynptr, 0, 1); + data = bpf_dynptr_slice(&dynptr, 0, buf, sizeof(buf)); if (!data) goto out; /* this should fail - file dynptr should be discarded first to prevent resource leak */ bpf_put_file(file); - *data = 'x'; - return 0; + return data[0]; out: bpf_dynptr_file_discard(&dynptr); |